Adhesive vs thinset?

First time ever doing tiling, help is appreciated. I am tiling a 4’x4’ half bath-I am in the process of cutting the cement boards to shape, and grabbed a tub of DAP weld wood multi-purpose floor adhesive along with cement screws from my small local hardware store. The stuff I got says it bonds to “fully cured concrete and flooring grade plywood”. My plan was to glue and screw the cement board to the subfloor, then put thinset down followed by the tile. All the sources I’ve consulted say that you want thinset on both sides of the cement board.

Would this stuff be suitable for bonding the concrete board to the subfloor? If not, why? In other words, what does thinset offer that adhesive doesn’t?

Thanks so much!